On Sunday, the whole family got together to discuss Tomb-Sweeping Day's going to his hometown. Chatting and chatting, a question suddenly popped up in my heart: How far is it from here to my hometown? "I asked my mother, who smiled and said," What do you think? You have studied for so many years, there must be a way to know, right? "
I thought about it, and it flashed, by the way, we can use the scale knowledge we have recently learned to calculate it. I immediately took the map and found Taizhou, but I couldn't find the Gaogu Town where my hometown was located. What shall we do? I thought hard and suddenly had a brainwave: we can find the nearest town-huangqiao town, and measure the distance from Taizhou to huangqiao town on the map, and then subtract some, which is the approximate distance from Taizhou to my hometown on the map! As soon as I got started, I immediately measured the distance from Taizhou to Huangqiao on the map, which was 0. 6 cm. Because my hometown is closer to Taizhou than Huangqiao, I changed 0.6cm from 0. 1cm to 0.5cm. Because the scale of this map is 1: 6000000, I used 0. 5× 6,000,000 = 3,000,000 cm, 3,000,000 cm = 30 km.
I immediately reported my answer to my mother: about 30 kilometers. I thought I would be praised by my mother, and my mother said doubtfully, it seems not that close, right? "After listening to my mother's words, I am also puzzled: How did this happen?" I came to the front of the map again and measured it again. Measuring, I suddenly found the mystery: I measured the straight line distance between two points on the map, but the actual road is not a straight line, so the actual distance must be farther than calculated according to the map.
I told my mother what I found, and my mother suddenly realized: Yes! That's it! How clever you are! "
At school, I learned how to calculate the volume. I tried to calculate the volume of things around me. Suddenly, my eyes focused on my unopened breeze tissue. When I owned it, I only counted the volume of a tissue.
Since it is a single sheet, it is necessary to calculate the whole package first. I took out my ruler and measured the length, width and height respectively.
Length: 7. The volume of 4 cm is 7.4× 5. 6×2。 5= 103。 6 cubic centimeters
Width: 5, 6 cm. However, it suddenly occurred to me that facial tissues can be flattened, which is wrong.
G: 2。 Will 5 cm reduce the volume? I thought for a few minutes, and it suddenly occurred to me that since it was unopened, it should be unopened. Thinking of this, I saw my data again. Can be measured or pressed. Finally, carefully measure and change the data again.
Length: 7. 5 cm volume: 7.5 × 5. 5×2。 5 = cubic centimeter
Width: 5, 5 cm. Almost succeeded, but I suddenly found that packaging plastic paper is also a body.
G: 2。 5 cm, but what can I do? After thinking for a long time, suddenly, I thought of a very primitive way. I took out the tissue inside and folded the plastic wrapping paper in half, which became a small cube.
Length: 2. 1 cm volume: 2. 1× 1。 8×0。 3= 1。 134 cubic centimeter
Width: 1.8 cm. Although it may be wrong, I can't think of another way.
High: 0. 3 cm
The final formula: (103, 125— 1. 134)÷ 10 (there are 10 sheets in a pack of facial tissues) = 10. 199 1 cm3
After this time, I finally like writing math papers.
Math essay composition 3 met an interesting test at school today, which was a psychological test of crystal ball invented by Indians.
I opened the page and looked at the rules. Here's the thing: choose a number from 10-99, add the ten digits and the single digits, and then subtract the added number from the original number. Finally, remember the pattern of numbers. Click on the crystal ball and the pattern you remember will appear (there is a number 10-99 next to the crystal ball and a pattern next to the number). Such as: 23 2+3 = 5 23-5 = 18.
After I was optimistic, I chose 787+8 = 1578- 1563. I looked at the pattern next to 63 again, then clicked the crystal ball and found that the picture that appeared was really the one I wrote down. I chose some numbers and calculated that the crystal ball can accurately show the patterns I wrote. How amazing!
I thought to myself: why does the crystal ball know the pattern I wrote?
So, I did a stupid little experiment: count all the numbers from 10-99. The original numbers are all multiples of 9: 9. 18。 27。 36。 45。 54。 63。 72。 I looked at the patterns next to these numbers again, and they were all the same. I said, "Oh, so the crystal ball will know the pattern I wrote! Ha ha ha! "
I found that mathematics is actually everywhere. As long as we are good at discovering, observing and thinking, the ocean of mathematics will make us soar!
Watermelon is the most popular fruit in summer. Today, my mother bought a big round watermelon. So, we are ready to eat watermelon!
My little sister asked me, "Sister Jiajia, how much do you want to eat?" "I thought about it and said," I'll eat this watermelon 1/2. What is 1/2? " She asked that 1/2 is a fraction, that is, dividing a thing into two parts on average and taking 1 of them. "I said." Oh, "Little Sister seems to understand." I eat the rest of this watermelon 1/2. "Mother interjected. The little sister asked, "Did the rest 1/2 eat all the rest of Sister Jiajia?" "Then I have nothing to eat?" "Ha ha!" My mother and I both laughed. "That's not true." Mom said with a smile. I replied, "The rest 1/2 is to regard the rest of me as a whole, and then divide this part into two parts on average, and take 1 of them." "That's right! Then I still have watermelon to eat! " Little sister suddenly realized. My little sister said mischievously, "I will eat 1/2 first in the future, so my 1/2 will be much more than yours." It's not worthwhile this time! " I lied to you. How can I eat so much? You can eat as much as you want! "We all laughed!
Do you know the score now? There are still many scores! Waiting for you to find out. Let's embark on the journey of finding mathematics together!
The annual Double 1 1 "Chop Hands Festival" is coming.
This afternoon, my mother sat on the sofa, leafing through Tmall's products, and prepared to snap up on the Double Eleven tomorrow. I've always wanted to buy a tool for making milk tea. My mother is a down-to-earth idea, and useless things are generally not bought back. I'm worried that my mother won't buy it after I put forward the demand, saying that I spend money indiscriminately. I couldn't help saying what I wanted.
Mom, can you buy me a toy? I asked softly. Mom said I could buy it as long as I could answer her a math problem, and I readily agreed. We searched the tools for making milk tea, and there were many flagship stores, two of which sold the best, each with a discount. Both are 68. 5 yuan, but shop A gets two for one, and shop B gets a 30% discount. I want to buy three sets. My mother asked me which was cheaper. I said shop A is 68. 5× 2 = 137 yuan (3 sets), and the price of Store B is 68. 5×3=205。 Five dollars, 205. 5×0。 7= 143。 85 yuan (3 sets). 143。 85 is greater than 137, so shop a has high cost performance. When I worked out the answer accurately, my mother happily bought a tool for making milk tea.
Mathematical knowledge is everywhere in life. I want to find the fun of mathematics and swim in the ocean of numbers.
I have always been poor in speed. I stumbled upon a problem and did it. Let me share it with you! During the period of Spring Festival travel rush in 20xx, a large-scale snowstorm occurred in southern China, which led to a power outage of a certain circuit. The local power supply bureau organized electricians to carry out emergency repair. The power supply bureau is 15km away from the emergency repair site. The emergency repair truck loaded with the required materials starts from the power supply bureau first. 15 minutes later, the electrician takes the Jixi truck to start from the original place. As a result, they arrived at the repair site at the same time. It is known that the speed of jeep is 1 of the speed of emergency repair vehicle. Five times, find the speed of these two cars.
Solution: 1 Assume that the speed of the emergency repair vehicle is x km/h and the speed of the jeep is 1. 5 xkm/h. Jeeps are faster than emergency vehicles 15km (i.e. 0. 25 hours) equation 15/X- 15/ 1. 5X=0 .25 x = 20km/h, then 1. 5x = 30km km/h
Answer: The speed of emergency repair vehicle is 20 km/h, and that of jeep is 30 km/h. 。
2。 Because the distance (S= 15KM) is the same, the time for people to walk is X. The time for materials to walk is X+ 15, that is, (15 ÷ x) ÷ (15 ÷ (x+/kloc). 5, a linear equation, X=30 minutes, which is 0. 5 hours, then the speed of jeep is 30KM/H, and the speed of emergency repair vehicle is 20 km/h.
Answer: The speed of emergency repair vehicle is 20 km/h, and that of jeep is 30 km/h. 。
3。 It takes x hours to set up a jeep.
According to the meaning of the question: x+ 15= 1. 5x
One day, the math teacher asked a question: What is the score of 1+2+3+4+5+6 ... 100? So, what about all the way up to 1000 and 10000? Calculate in a simple way.
Formula:1+2+3+4+5+6+7 ...+100 = 5050 5050×10 = 50500 50500×10 = 505000.
A: The number of 1 added to 100 is 5050, and the numbers of 1000 and 10000 are 50500 and 505000 respectively.
Simple algorithm: some students may think this is too long and need a calculator! No, that's wrong. As long as you look carefully, you can find that 1 and 99 add up to 100, 2 and 98 add up to 100, 3 and 97 add up to 100, 4 and 96, 5 and 95, 6 and 94, 7 and 93, 8. 1 1 and 89 ... so it goes all the way to 100. As a result, you can get 50 100, which is 5000, but there is still a single number of 50, so you can take 5000+50 =5050 and get 1 all the way to 6500. But some people will ask, 1 has been added to 1000 and 10000. Why doesn't it count? Because the rates of 100 and 1000 are 100 times, and the rates of 1000 and 1000 are also 10 times, you can take 1 and increase it to/kloc. Line, 1 has been added to 100000, 1000000, 10000000, etc., all of which can be calculated in this way. Of course, you can learn more about the law of this problem!
Today, my mother is going to buy a light bulb. When I arrived at the supermarket, I found that there are two kinds of light bulbs in the supermarket: one is energy-saving light bulbs and the other is ordinary light bulbs. Although the energy-saving light bulb only needs one degree of electricity for 200 hours, which is 170 hours more than the ordinary light bulb, it needs 5 yuan. An ordinary light bulb costs only 1 yuan, which is cheaper than energy-saving light bulbs by 4 yuan, but it uses one degree of electricity every 30 hours.
My mother asked me: "test you, if I want to buy a light bulb to go home, what kind of light bulb is the most cost-effective?"
I thought about it and said unhurriedly, "It can be calculated as follows:
5/ 1=5
30*5= 150 (hours) 200 hours > 150 hours
You can also calculate it like this:
5/ 1=5
200/5=40 (hours) 30 hours
From these steps, it can be concluded that energy-saving light bulbs save money. "
My mother asked me again, "OK. Think again, is there any other calculation method? "
I thought for a while, then said word for word, "Can I use what I have learned this semester?" Percentage? Let's do the math. You can also calculate it like this:
5/200* 100=0.025* 100=2.5
1/30* 100≈0.033* 100=3.3
3.3 & gt2.5
Or calculate it like this:
200/5* 100=40* 100=4000
30/ 1* 100=30* 100=3000
4000 & gt3000
So energy-saving light bulbs are also cheap. . "
My mother and I bought more cost-effective energy-saving light bulbs and went back.
After this incident, I understand the truth that "there is mathematics everywhere in life".
Today, the teacher told us a key problem in the three-level training: a square with a length of 100 m and a width of 80 m, leaving a sidewalk with a width of 4 m in the middle, and dividing the square into four pieces on average. What is the area of each block?
After seeing the topic, someone used their brains to find a way; Someone stared at the ceiling; I racked my brains and thought hard, and finally came up with a method, so I quickly raised my little hand and the teacher told me to get up and answer. I said loudly: "100-4=96 meters; 96÷2=48 meters; 80-4 = 76m； 76÷2=38 meters; 38×48= 1824 square meters ".
"Can you tell me about your thinking method?" Teacher Shen asked. "First subtract 4 from the length, calculate the length of two pieces, and then divide by 2 to get the length of a small square; The width is also used in the same way, and finally the area of a piece is obtained by multiplying the length and width. "
Teacher Shen asked again, "Is there any other way?"
Yu Xia stood up to answer. He even said several formulas, but we didn't understand them.
The teacher asked everyone to think of other ways. Everyone looked confident, but they bowed their heads for fear of making a mistake.
So teacher Shen took us to understand the formula, and the difficulty was solved.
Through this lesson, I understand a truth: nothing is difficult in the world, and if you put your mind to it, you will definitely come up with a solution to the problem!
One day, my mother and I went shopping. Mom went into the supermarket to buy things and let me stand at the place where I paid. I have nothing to do, just watch the assistant aunt collect money. After reading it, I suddenly found that the money collected by the assistant aunt was 1 yuan, 2 yuan, 5 yuan, 10 yuan, 20 yuan and 50 yuan. I feel very strange: Why isn't RMB from 3 yuan, 4 yuan, 6 yuan, 7 yuan, 8 yuan, 9 yuan or 30 yuan, 40 yuan or 60 yuan? I ran to ask my mother, and my mother encouraged me to say, "Think hard and calculate well. My mother believes you can figure out the reason." I calmed down and thought it over. After a while, I jumped up happily: "I know, because as long as you have 1 yuan, 2 yuan and 5 yuan, you can form 3 yuan, 4 yuan, 6 yuan, 7 yuan, 8 yuan and 9 yuan at will, and as long as you have 10 yuan, 20 yuan and 50 yuan, you can also form 30 yuan and 40 yuan." Why 2 yuan and 5 yuan? "I said," it is not convenient to use 1 yuan to form a larger number. "
Now my mother shows a satisfied smile and praises me for observing more and thinking more. I am really more comfortable than eating my favorite ice cream. Here, I also want to tell other children: in fact, there are math problems everywhere in life. As long as you pay more attention to observation and thinking, you will find many unexpected discoveries. Try it if you don't believe me!
Math essay 1 1 is full of fun. There are many interesting things in our math kingdom.
For example, in a math expansion problem my dad bought me, there was a thinking question that said, "A bus from Dongcheng to Xicheng, with a speed of 45 kilometers per hour, took 2. It will stop after 5 hours, just 18 km from the center of the East-West City. How many kilometers is the East-West City? " At this time, I wrote this on the math draft paper: 45×2. 5= 1 12。 5 (km), 1 12. 5+ 18= 130。 5 (km), 130. 5× 2 = 26 1 (km), a: the distance between east and west city is 26 1 km.
But I looked at it again and found something was wrong. It turns out that I overlooked an important thing, that is, it is just 18 km from the center of the East and West City, in which "Li" is not at the center. Or is it past the midpoint? If it's not the midpoint yet, and it's still 18 kilometers away from the midpoint, that's what I just wrote. But if it is the midpoint 18km, it should be written as follows: 45×2. 5= 1 12。 5 (km), 1 12. 5—— 18=94。 5 (km), 94 5× 2 = 189 (km).
So how do you write it? I asked my father for help. After I told him about it, I showed him the recipe. As a result, my father said, "well ... the two formulas you wrote are correct." You can write anything. "
In daily study, there are often many math problems with multiple solutions, which are easily overlooked in practice or examination. This requires us to carefully examine the problem, carefully scrutinize it according to our own life experience, and fully and correctly understand the meaning of the problem. Otherwise, it is easy to ignore other answers.
As soon as this morning came, her mother announced that the whole family would go to Auchan for breakfast and go shopping in the supermarket today, because there was no water supply at home.
When we get there, we are going to have breakfast first, and then we will come to Shenfu to eat noodles. However, a bowl of noodles here costs 3 to 40 yuan, which is very expensive. What's even more frightening is that a chicken claw here costs 5 yuan. We thought it was too expensive and uneconomical, so we came to "pill-to-pill fun". Unexpectedly, just separated by a wall, the price gap is so big: a bowl of noodles here is 9 yuan. After breakfast, we began to visit the supermarket! We bought a bag of green oranges that my father and I like best first. The total quantity is 1 1, and the price is 5.2 yuan, which is about 50 cents each. We went to buy five chicken feet and a 4.8 yuan. The price of this chicken feet is a far cry from the price of Shenfu noodles. On the one hand, it is less than 1 yuan/piece, on the other hand, it is 5 yuan/piece. I went to the fruit area and bought a bag of green snake fruits, three *** 17.7 yuan. Such a small green snake fruit costs almost 6 yuan, which is so expensive! Next, we bought a cantaloupe, 1 1.3 yuan. Unexpectedly, three small green snake fruits are more expensive than a big cantaloupe in 6.4 yuan. Since I tasted the yellow peaches at my neighbor Taotao's house, we have bought three big yellow peaches, a ***9.6 yuan. Average 3.2 yuan per yellow peach. We bought everything that needed to be checked, including things that were not mentioned here. A 500 yuan.
This time, I learned a lot of math knowledge from shopping. I am so happy today!
Math essay composition 13 Today is the Mid-Autumn Festival, and our family is so happy. Mom and Dad said, "Today is a good day. How about we play the game of grabbing paper? " I nodded. Father took four pieces of paper with the same shape and size, and put two pieces of red paper and two pieces of blue paper into this bag respectively. He said: "This is not a transparent bag. There are two red papers and two blue papers in it. You touch two pieces of red paper or two pieces of blue paper, and I'll give you five dollars, or you can give me five dollars, okay? " I said, "Then I quit.
"Dad asked," why? Don't you also have the opportunity to make money? " I said, "although I can make money, I don't have as many opportunities as you!" You see, a * * * has four pieces of paper. If the first one I touch is red, and there are two pieces of blue paper and one piece of red paper left in the bag, then the chance of touching red is only 1/3, and the chance of touching blue is 2/3. If I touch blue first, then the chance of touching blue again is only 1/3, and the chance of touching red is 2/3, so of course you can make money more easily than me. "Dad said," Yes, son, you are smart, so I won't be fascinated by you. Well, I will reward you with five dollars for your good performance today! " "I'm so happy, today is really a good day.
Math essay composition 14 dad is a complete math fan, and he usually likes to test me with some math problems. No, I was idle today and asked me a question. I asked, "What questions will Dad ask today?" ? I will accompany you to the end: "Dad saw that I was full of confidence and said with a smile on my face:" Don't cry if you lose. Listen to the question: A master and an apprentice are doing 26 parts together. When the apprentice went to the workshop first, he took some parts and put them next to his machine tool. When the master came, he saw that the apprentice had too many parts to process, and he took half of them from the apprentice except the parts left for him. The apprentice felt that he should do more and took half from the master. The master refused, so the apprentice had to give him five more roles. Finally, the master processed two more parts than the apprentice. How many parts is the apprentice going to process at first? "I can't help but think: we can find out the parts that the apprentice finally processed first (26 ÷ 2) ÷ 2 = 12. When the apprentice didn't give the master five copies, the apprentice had 12+5 = 17 copies. Before the apprentice took half of the parts from the master, the master had 9× 2 = 18 parts. At this time, the apprentice only had 26- 18 parts, so the apprentice had 8 parts before the master took half of the parts from the apprentice. At this moment, my father patted me on the shoulder and said, "Have you figured it out? "."I just came to my senses and replied, "My apprentice was originally going to process 16 parts."
Dad asked mysteriously, "Are you sure? Do you want to change it? " I shook my head confidently and said, "Don't change." "Congratulations ... you got it right!"
I jumped three feet high with joy, and my heart was as happy as honey.
Math essay composition 15 I went to Jinji Lake with my mother. I saw many traffic signs on the road. Some say 1000 meters ahead, some say 500 meters, some say 3 kilometers, and so on. I asked my mother curiously, "Mom, how many meters is 10 km?" "Mom smiled and told me that it was10000m!" Huh? I thought it was 10 meter! "I said to my mother.
"Oh, son, do you know how many meters a kilometer is?" Mom asked.
"100 meter?" I tried to answer.
"Wrong, one kilometer is equal to 1000m!" Mom said.
"Then why don't people say that one kilometer is 1000 meters and use kilometers to calculate it?" I asked.
"That's too much trouble. If it is hundreds of thousands or even tens of thousands of kilometers, how many zeros do you want to write in meters? For the convenience of recording, people use kilometers instead, 1000 meters, 10000 meters, 10000 meters, etc. , removing the last three zeros is kilometers! " Mom said.
"I see, Mom, 1000 meters is 1 km, 10000 meters is1km, 100000 meters is1km!" I told my mother excitedly.
"Son, you are great!" Mom said approvingly.
Haha, there is a knack for calculating kilometers!
Model essay on teacher education and training 1
Through the study of continuing education and training in this school year, we have